Hydraulic brake cylinder



May 14, 1929.

F. H. GLEAsoN ET AL.

HYDRAULIC BRAKE CYLINDER 1924 2 SheetsmSheet Filed June 5 lll/1 lill,

May 14, 1929. F, H, GLEASON ET AL 1,712,882

HYDRAULIC BRAKE CYLINDER Filed June 3, 1924 2 Sheets-Sheet atented May14, 1929.

UNITED STATES PATENT OFFICE.

FREDERICK H. GLEASON, OF AUBURN, NEVI YORK, AND LELAND FQ GOODSPEED, FKALAMAZOQ MICHIGAN. ASSIGNORS TO BOWEN PRODUCTS CORPORATION, 0F AUBURN,NEW YORK, A CORPORATION OIF NEW YORK.

HYDRAULIC BRAKE CYLINDER.

Application filed June 3,

'llhis invention relates to certain new and improved hydraulic cylindersfor use with hydraulifv brakes or other devices controlled by fluidhydraulic pressure. The hydraulic control system as used tor applyingthe brakes ot an automobile chassis requires a masteroperating hydrauliccylinder and 1four brakeapplying` hydraulic cylinders with doubleopposed pistons to transmit the hydraulic pressure to the brake bands orshoes on the brake drums with which the vehicle wheels are equipped.rlFhe travel of the brake pedal which operates the master hydrauliccylinder, which in turn operates the brake-apply ing hydraulic cylindersis limited by the distance thev operators foot can conveniently travel,coupled with the pressure per square inch required on the fluid toproperly apply the pressure necessary to apply the brake, through thebrake applying' hydraulic cylinders located near the brake-drun'is onthe vehicle wheels. A very small leak in the packings ot either themaster hydraulic cylinder or the brake-applying 'hydraulic cylinderswill render the system inoperative because the brake pedal will reachthe limit of its travel, and the pressure on the'iluid in the :ylindersand connectingr tubes will be lost.

rlhe object of this invention is to eliminate suoli difiiculty by meansof an improved construction of hydraulic cylinder in which paci'- ingsare eliminated and leakage prevented.

@ther objects and advantages relate to the details ot the structure allas will more fully appear trom the following description, taken inconnection with the accompanyingdraw ings, in which Figure 1 is a topplan view ol.E a hydraulic braking system applied to an automobilechassis.

Figure 2 is a section on line 2 2, Figure 1.

.Figure 3 is a section on line 3 3, Figure 2.

liigure 4 if; a section on line 4 4, Figure 1.

litigare 5 is a section on line 5 5, Figure 4.

.lin a general way, the known hydraulic brake system comprises abrake-pedal 1 in the lorm of a bell crank, preferably mounted in anysuitable manner as upon the shaft --2 and having its lower end connectedto the piston ro( 3 which actuates the piston in the master cylinder 4The master cylinder ll and the remaining portions of the hydraulicsystem are maintained full o'l" iluid taken from a small reservoir 5con- 1924. Serial No. 717,590.

nected to the master' cylinder 4 by a tube 6 so that the reservoirsupplies a small amount oil' fluid to the system each time the tootpedal isoperated it' the system is not entirely iilled with fluid. Fromthe master cylin der,` two supply supply lines 7 extend to they tubing,`T 8 at opposite sides of the frame ot the vehicle and from the T 8 tubesQ extend to the flexible tubes 10 connected to the respectivebrake-applying cylinders 11 located on the outer ends ol the axles ofthe chassis.

The construct-ion above described is well known and used with presenthydraulic braking* systems.

'lhe invention here resides particularly in the. construction ot themaster operating cyliuder 'l and the brake-applyin,r cylinders 11 bothof which constructions involve similar features of structure andoperation.

The brake-applyineV cylinders 11 as best shown in Figure 2. have doubleopposed means for operating the brake rocker levers 1Q- which areattached to brake bands 4S- on the brake drums of the wheels.

rThe tube 10 is attached to the casing M ot' the brake-a pplyiup,rcylinders 12 by means ol' a tubingl nut 52 and tubing sleeve. M oliordinary construction. The casing;` 14 is provided with a cylindricalbore 15 extending` from end to end thereof and with a pipe plug 1G atits upper part to permit 'all air or gas to be forced out of the tubesand passages.

In ell'ectthe casingr M constitutes two cylinders including;- duplicatebrake-operating mechanisms and a description of one of suchbrake-operating cylinders will serve to describe both.

As illustrated7 a round shaft 17 is provided with a reduced diameter atone end and threaded to receive a nut 18 A con voluted collapsiblediaphragm or bellows 1S) has its open end clamped' to one of the openends oi? the casing M and for this purpose the base ot' the bellows 19is flanc-ed outwardly and clamped between one end of the cylinder M anda threaded nut 2() whiehalso acts as a guide for shaft 17 and throughthe central portion of which the shaft --17 projects outwardly, and thejoint. between the llanged portion of the diaphragm or bellows and thecasing lll-and nut 20- may be made fluidtight in any suitable manner, asby gasket -21-.

The reduced end portion of shaft 17- extends through the otherwiseclosed end of a cylindrical steel shell -22- and through the otherwiseclosed end of bellows -19- through the washer 2S- guide disk -9A, lockwasher -25-, and the nut 1S- is threaded upon the reduced end of theshaft so as to clamp the parts named between the shoulder' on the shaftat lthe base of the reduced portion and the nut.

The joint between the parts is made fluidtight by means of the washer orgasket #23- and an additional washer or gasket -55- positioned betweenthe partially closed ends of the steel shell -22- and the shoulder uponthe shaft -`l7. y

Preferably in expanded pos1tion,.as illustrated, the bellows is ofslightly less diameter .than the interior diameter of the casing 14- andthe shell -22- is of somewhat less diameter than the internal diameterof the bellows -19- to permit unobstructed contracting or compressing ofthe bellows or convoluted diaphragm -19'.

The circular guiding disk -24-- has a loose sliding lit in the cylinderor casing I4- and is provided with edge slots 26- to permit the fluid tofreely pass therethrough.

A spring -27- surrounding the shaft -17- normally maintains the shaft-17 at its inner position when there 1s no presf sure on the fluid inthe cylindrical bore of nection with the operating mechanism in thecasing or cylinder 14- except that the mechanism is of a unitary ratherthan du plicate character. The structure of the master cylinder, as bestshown `in Figure 4, comprises a casing or cylinder -28- having apassageway -29- at one end in communi` cation with the supply lines -7-.Within thecylinder -28- is arranged a bellows or convoluted diaphragm-30- having its base outwardly flanged and clamped between the base ofthe cylinder and a cap plate -31-, suitable gaskets being interposed formaintaining the joint fluid-tight. The cap may be connected tothe'cylinder in any suitable manner, as by bolts -32- equipped ifdesired with lock-washers -33-. Within the bellows is arranged a steeltube S4- normally projecting at one end a distance equal to the travelof the piston rod closed at one end except for an opening through` whichthe jointed shaft or rod -35- extends and the shaft may, as shown, beprovided with a shoulder which contacts with the inner wall of thepartially closed end of the tube the otherwise closed end of the bellowsor diaphragm -30- and through a guiding disk -36- having a peripheralrecess or recesses, suitable washers or gaskets -37- being interposedfor rendering the joint fluid-tight. The end wall of the steel tube, theend wall .of the bellows and the guiding disk are clamped tightlyagainst the shoulder on the shaft -35- by means of a nut -39- and lockwasher 40. The jointed shaft is preferably of a character in which thetwo parts are connected by a ball and socket joint 41-. A spring -42- isinterposed between the front end of the cylinder *528- and t-he frontsurface of the guiding disk 3G-- so as to normally maintain theconvoluted diaphragm o1' bellows -30 in contracted or compressedcondition, thereby maintaining the foot pedal -lin an operative positionso that the brakes can be applied.

The operation of these hydraulic cylinders is as follows:

When the foot pedal -1- is depressed, the bellows --30- in the mastercylinder -28- is expanded, forcing the fluid from the master cylinderthrough tubes 7, -9- and -10- to the cylindrical bore of the casing -14.The iuid pressure acting equally in all directions in the'casing --14-compresses the bellows and forces both of the shal'ts -17- outwardly,thereby contracting the brake bands i3-e on the brake drums through themedium of the rocking levers -l2-. The cylindrical steel shell -22-supports the convoluted diaphragm -19- and prevents the {iuid pressurein the bore of casing lllfrom collapsing the diaphragm. Vhen the fluidpressure is relieved by releasing foot pedal -1-, spring -42- returnsthe diaphragm 30- to its contracted position, thereby releasing;` thepressure in the supply lines and permitting lsprings -27-- to returnshafts 17--, the bellows and the brake-operating parts connected withthem to starting position, and the brakes are thereby released.

This construction of hydraulic cylinder provides a -means for utilizinghydraulic ilu-id pressure with the elimination of packings and the like,thereby eliminating leakage and escape of the operating fluid.

Altho we have shown and described speci lic constructions asillustrative of perhaps preferred embodiments of our invention, we donot desire to restrict ourselves to the details of the structure, asvarious changes may be made within the scope of the appended claims.

Ve claim:

1. A hydraulic mechanism and braking apparatus to be actuated thereby,said mechanism comprising a casing, a pair of convolute cup-shapediaphragms reversely arranged i closcdhend of the within the easing withtheir open ends disposed outwardly and secured to the casing in atluid-tight manner, shafts secured to the closed ends ot the respectivecup-shape diaphragms and moving with the diaphraglns as they expand,,and contract lor actuating said apparatus reversely, and means forsupplying fluid under pressure to said casing between said diaphragnisfor simultaneously actuating the latter.

2. A l ),f'draulie cylinder comprising a substantially cylindricalcasing, a,bellows arranged within the casing with its open end clampedto the open end of the casing, a shaft havingl a fluid-tight engagementwith the bellows, and a tube within and ot' slightly less diameter thanthe bellows, and carried by said shaft.

El. 1li hydraulic cylinder comprising a substantially cylindricalcasing, a bellows arranged within the casing with its open end clampedto the open end ol the casing, a shaft having a fluid-tight engagementwith and eX- tending through the closed end of the bellows, and alieripherally recessed guide disk mounted on the shat't in liront ot theclosed end of the bellows and guiding the bellows in its u'iovenientwithin thc casing.

4i. A hydraulic cylinder comprising a substantially cylindrical casing,a bellows arranged within the casing with itsopen end elan'iped lo theopen end oi the casing, a shaft having` a fluid-tight engagement withthe closed end ot the bellows, a tube within and ot slightly lessdiameter than the bellows, and a guide disk mounted on the shaft infront of the closed end ot' the bellows and guiding the bellows inisiuovement within the casing.

5. le hydraulic cylinder comprising a subay stautially cylindricalcasing, a bellows arranged within the casing with its open end clampedto the. open end ot the casing, a shaftliaiing a fluid-tight: engagementwith ,the

closed end et the bellows, and a tube within and ot' slight ly lessdiameter than the bellows and carried by said shaft, and a guide diskmounted on the shaft 'forward ot the bellows and hai-'ing an openingtherethrough for the passage of fluid and adapted to guide the bellowsin its. movement within the casing.

ti. l hydraulic cylinder comprising a substantially cylindrical casing,a bellows arranged within the easing with lits open end clamped to theopen end of the casing, a shaft having a fluid-tight engagement with theclosed end ot the bellows, a tube within and of slightly less diameterthan the bellows and carried by said shaft, and spring means within thetube for normally maintaining the bellows in extended position.

7. A hydraulic cylinder comprising a substantially cylindrical casing7 abellows arranged within the casing with its open cud clamped to the openend'oll the casing, a shaft having a duid-tight engagement with andtract, means for extending through the closed end of thc bellows, aperipherally recessed guide disk mounted on the shaft in front of theclosed end of the bellows and guiding` the bellows in its movementwithin the casing, and spring means for normally maintaining the bellowsbellows in its movement within the casing,

and spring means within the tube for normally maintaining the bellows inextended position.

9. A hydraulic cylinder comprising a substantially cylindrical casing, abellows arranged within the casing with its open end clamped to the openend of the casing, a shaft having a duid-tight engagement with theclosed end ot the bellows, a tube within and of slightly less diameter'than the bellows and carried by said shait, a guide disk mounted on theshaft forward ot' the bellows and having an opening therethrough for thepassage of fluid andadapted to guide the bellows in its movement withinthe casing, and spring means within the tube for normally maintainingthe bellowsv in extended position.

l0. A hydraulic cylinder comprising an elongated casing, opposed bellowsarranged within the casing with their open ends disposed oiitwardly andsecured-to the easing in a fluid tight manner, shafts secured to theclose-'l ends ot respective bellows and moving with the bellows as theyexpand and contract, and means for admitting fluid into the casing.

1l. A hydraulic cylinder comprising an elongated casing, opposed bellowsarranged within the casing with their open ends disposed outwardly andsecured to the casing in a fluid-tight manner, shafts secured to theclosed ends ing with the bellows as they expand and contract, and meansfor admitting fluid within the casing at a point between the closed endsof the bellows.

l2. A hydraulic cylinder comprising anl elongated casing, opposedbellows arranged `within the casing with their open endsl disposedoutwardly and secured to the casing'in a fluid-tight manner, shaftssecured to the closed ends of respective bellows and-moving with thebellows as they expand and conadniitting fluid into the casing, andspring means for normally maintaining the bellows in extended position.i

13. A hydraulic cylinder comprising an elongated casing, opposed bellowsarranged of respectivebellows and moviio within the casing with theiropen ends disposed outwardly and Secured to the casing in a fluid-tightmanner, shafts secured to the respective bellows and moving with thebellows, means for admitting fluid into the casing, spring means :tornormally maintaining the bellows in extended `position, and means forinteriorly supporting the bellows during their movement.

14. A hydraulic mechanism and braking apparatus to be actuated thereby,said mecha- 'nism comprising a casing, a pair of convolute cup-shape`diuphragfms rcversely arranged Within the casing with their Open endsdisposed outwardly and secured to the casing in a fluid-tight manner,shafts secured to the closed ends of the respective cup-shape diaphragmsand moving with the diaphragms as they expand and contract for actuatingifi'lassz said apparatus reversely, means for supplying liquid underpressure to said casing between said diaphragnis for simultaneouslyactuating: the latter,- and spring means for normally maintaininzgr thecup-shape diaplnagms in extended position.

15. A hydraulic cylinder comprising a cylindrical casing, a convolutedcup-shaped diaphragm arranged within the casing, a tube arranged Withinthe diaphragm, a rod extending through the tube and the inner end of thediaphragm and secured thereto in u fluid-tight manner, and spring meansexerting pressure upon the diaphragm.

" ln witness whereor` we have hereunto set our hands this 14th day ofMay 1924.

FREDERICK H. GLEASON. LELAND F. vlOODSPEED.

